> The question is, does the NT authors' use of> "God sent his only son..." imply the assumption of the pre-existance> of Jesus before his birth.

According to what I've read, "Only-begotten" (e.g. Jn 1:14) is a mistranslation
of monogenes, which means "only", "unique". Further, the implication is only
of a family name bearing son (an earlier one might have died, for example).

> Another way of asking the question is, "How early in the church tradition is> the doctrine of Jesus' preexistance?"

This interesting question seems more apprpriate for other lists, e.g. ELENCHUS,
BIBLE.

> I am primarily interested in the arguement that the "sent"> formulations are evidence of an early doctrine of Jesus' pre-existance which> reaches its full expression in John.

I wish I could be of more help, but I can say that basing an argument for
pre-existence on the use of a single, common word seems very flimsy to
me. What word meaning "sent" would not imply existence in any language?